The invention relates to a lighting system for producing white light, which lighting system comprises at least three light-emitting diodes, each one of the light-emitting diodes emitting, in operation, visible light in a preselected wavelength range.
Lighting systems on the basis of light-emitting diodes (LEDs) are used as a source of white light for general lighting applications.
U.S. Pat. No. 5,851,063 discloses a lighting system which employs three LEDs as a light source for; making white light. In this lighting system it is calculated that the maxima of the emission spectra of the LEDs are preferably selected in the wavelength ranges from 455 to 490 mn, 530 to 570 nm and 605 to 630 nm. For such a lighting system it is further calculated that a color rendering index in excess of 80 can be achieved.
Such lighting systems have the drawback that LEDs with spectral maxima in these spectral ranges and, simultaneously, a sufficient energy efficiency are not available. In a lighting system in which such LEDs are employed, particularly the luminous efficacy is adversely influenced.